ASP. NET Excel operation Memorandum

Question 1: Access Denied
There are three possibilities for access denied,
One is that the current user does not have access permissions.
The other is that the process with excel.exe already exists and the program is not cleared in time.
The specified Excel file is being used by another process.

Solution 1
Grant the aspnet permission to the specified Excel folder and add a piece of code in <system. web> of web. config.
<Identity impersonate = "true"> </identity>
That's all!

Solution 2
The excel.exe process exists in the supervisor. If so, manually end the process and change the Excel Code,
The process is automatically ended after Excel execution.

Solution 3
This is the lowest-level error! I used an Excel document, but I don't know! Then, when the program accesses Excel, it says that the access is denied!